The present invention relates to an electric-component connecting structure for connecting electric components to bus bars and, more particularly, to the structure for securely fixing and connecting electric components to bus bars without the use of solder.
Conventionally, in order to structure an electric circuit by arranging electric components, it has been a general practice to use a substrate for connecting conductors to the electric components. Naturally, solder connection has been used in connection to the electric components.
However, in solder connection, there is a problem with solder-crack occurrence in the temperature impact test based on the user""s specification. Meanwhile, in the recent environmental problems, there is an emphasized problem for establishing a Pb-free structure free of Pb use.
Accordingly, in order to solve such a problem, it is an object of the present invention to provide an electric-component connecting structure that is free from crack occurrence in the temperature impact test, higher in reliability than solder connection and of a Pb-free structure.
The outline of the present invention will be explained with FIG. 1. In FIG. 1, 1 is a resin case, 2 to 5 are bus bars, 6 to 10 are electric components, 11 is a hole, 21 is a projection and 61 is a lead leg.
The object of the invention can be achieved by the following structures (1) to (3).
(1) The electric component connecting structure includes: a resin case 1; a bus bar 2 to 5 made of metal fixed on the resin case; and a welding projection 21 formed in the bus bar 2 to 5, for connection to a lead leg 61 of an electric component 6 to 10, wherein electric connection is made between the electric component 6 to 10 and the bus bar 2 to 5 by welding the welding projection 21 with the lead leg 61 of the electric component.
(2) In the electric component connecting structure of the above (1), fixing part is formed on the resin case to position or temporarily fix the electric component.
(3) The electric component connecting structure includes: a resin substrate; a bus bar made of metal fixed on the resin case; and a welding projection formed in the bus bar, for connection to a lead leg of an electric component, wherein electric connection is made between the electric component and the bus bar by welding the welding projection with the lead leg of the electric component.
This provides the below operation effects.
(1) By providing a bus bar 2 to 5 made of metal fixed on a resin case 1, forming a welding projection 21 for welding to a lead leg 61 of each of a plurality of electric components 6 to 10 and welding the welding projection 21 to the electric-component lead leg 61, electric connection is made between the electric component 6 to 10 and the bus bar 2 to 5. Accordingly, it is possible to provide an electric component connecting structure which is free from crack occurrence in the connection even due to temperature impact test, free of Pb and higher in reliability than solder connection.
(2) Because the resin case is formed with fixing part to position or temporarily fix the electric component, it is possible, in advance of welding, to correctly position between the electric component and the welding projection. Thus, welding connection can be made with efficiency and correctness.
(3) By providing a bus bar made of metal fixed on a resin substrate, providing a plurality of welding projections for welding to lead legs of a plurality of electric components and welding the welding projection with the electric-component lead leg, electric connection is made between the electric component and the bus bar. Accordingly, it is possible to provide an electric component connecting structure which is free from crack occurrence in the connection even due to temperature impact test, free of Pb and higher in reliability than solder connection.